Help!! Misfire cyl's 1,3,5 P0300
#31
The fuel would enter the cylinders the exact same way that the air needed for combustion does. And NO it is NOT a good idea to close off any holes in your crank case that have been designed into the engine. Just fix the problem that is causing your fuel puddle and be done with it.
#32
im running Bosch platium +2 plugs and Jegs brand cap and rotor. the cap is a brass terminal type unlike the Aluminun Delco type. and my wires are jegs brand 8.5mm super conductor wires... should i remove the plugs?
#33
Just finished swapping out the Spider with a new MFI conversion. Although it tends to accelerate smoother, still missing like crazy at idle. For the most part, only on clyinder #5. Will set a P035 code as well. If I drive around, will only pick up misfire when at 0 throttle and low vehicle speeds, and at idle.
Went back and tried putting old cap and rotor back on. Different wires from other cylinders, moving plugs. No Luck. Fire it up and it misses like crazy on Cylinder 5.
What else could ther bit electrically that would cause the misfire to occur mainly on cylinder 5? I'm truely stumped.
Went back and tried putting old cap and rotor back on. Different wires from other cylinders, moving plugs. No Luck. Fire it up and it misses like crazy on Cylinder 5.
What else could ther bit electrically that would cause the misfire to occur mainly on cylinder 5? I'm truely stumped.
#34
The bosch +2 plugs are known to cause misfires on these engines. I would drop in a set of delco plugs. The same can be said for non delco caps for some years of these engines.
#35
ok just got some ac delco plugs that the emission sticker calls for under the hood. should i change the cap back to the aluminun ac delco too? i have a 95 s 10 vortec "W" vin crab type dist...
Last edited by bigdaddykane93; 09-11-2009 at 06:58 PM. Reason: edit
#36
Update:
Trying to summarize the situation I have. This thread has gotten confusing.
Have a misfire at idle, predominantly cylinder #5, although others will misfire as well. Even the even bank cylinders.
Have replaced Cap, Rotor, Plugs (now AC Delco - no difference), Wires, Coil, PCV valve. Moved parts around and #5 stays the worse. Just replaced the spider to teh MFI. Really didn't impact the misfire on #5 at all. Pulled the Bank 1 cylinder head and lapped valves. Brought compression up to 150 to 160 psi range.
Looking for next steps. Since predominantly on #5, I am thinking electrical. I don't understand how the ICM works and whether that could cause this sort of problem, or something specific to the distributor. At this point, the problem is not very heat sensitive. A bit better when cold, but I think that is just due to the higher idle speed.
New development. I went out to try and see if I was getting and kind of cross-fire of erratic spark and all of the wires and plugs were clean. Nothing around the ICM and coil area. When I sprayed the distributor with water however, I notcied quite a bit of sparking that looked as though it was actually coming through the distributor it self. I woud see the sparking at various places around the cap all at the me time. This is a new cap and rotor, but maybe I am onto something here. Have never done this before so I don't know if some level of sparking is normal or not. I suspect not, but looking for some advice.
Trying to summarize the situation I have. This thread has gotten confusing.
Have a misfire at idle, predominantly cylinder #5, although others will misfire as well. Even the even bank cylinders.
Have replaced Cap, Rotor, Plugs (now AC Delco - no difference), Wires, Coil, PCV valve. Moved parts around and #5 stays the worse. Just replaced the spider to teh MFI. Really didn't impact the misfire on #5 at all. Pulled the Bank 1 cylinder head and lapped valves. Brought compression up to 150 to 160 psi range.
Looking for next steps. Since predominantly on #5, I am thinking electrical. I don't understand how the ICM works and whether that could cause this sort of problem, or something specific to the distributor. At this point, the problem is not very heat sensitive. A bit better when cold, but I think that is just due to the higher idle speed.
New development. I went out to try and see if I was getting and kind of cross-fire of erratic spark and all of the wires and plugs were clean. Nothing around the ICM and coil area. When I sprayed the distributor with water however, I notcied quite a bit of sparking that looked as though it was actually coming through the distributor it self. I woud see the sparking at various places around the cap all at the me time. This is a new cap and rotor, but maybe I am onto something here. Have never done this before so I don't know if some level of sparking is normal or not. I suspect not, but looking for some advice.
Last edited by vaportrail; 09-11-2009 at 10:18 PM. Reason: new information
#38
Hey, I thought I would chime in here. I just went through a terrible ordeal with a 2000 blazer "w" code engine. It had a miss on #2 primarily but some misses on other cylinders at a lower volume according to the counter on the tech II. This miss only occured after it ran for 10-15 minutes and then only under load. I looked at compression (good), replaced all the ignition components including a coil that looked like it got hot, checked the distributor which looked good but I shimmed it up so it only had .035" clearance. Vacuum looked good and steady and you could not see the misfire when using a spark light. I switched the injectors around on the spider even though the injector balance test showed within tolerance, still no resolution. No leaks through the intake or EGR either.
I ran across an aritcle where a very experienced tech found the solution with a crank position sensor. I was hesitant because there was no code so I convinced the chevy dealer to loan me a crank sensor since they couldn't find the problem either. Long story short...the crank position sensor caused the problem. She runs great now.
I ran across an aritcle where a very experienced tech found the solution with a crank position sensor. I was hesitant because there was no code so I convinced the chevy dealer to loan me a crank sensor since they couldn't find the problem either. Long story short...the crank position sensor caused the problem. She runs great now.
#39
Thanks for the hint. A bit of an update since my last post. I ended up putting a new cap and rotor on from Napa as well as swapping out plugs again (Delco) and it is running much better. I am getting an occassional miss on cylinders 1 and 6 now. Still mostly at idle, but I do see it under load as well. Going to monitor it for a while and see how it goes. Not setting a light in the last 2 days. I may try your idea of crankshaft sensor to see if tat may clear it up. I also have no codes for that, but you never know. I also gave the MAF sensor a second cleaning. Cylinder 5 which was my big culprit is now running quite clean. Still have a feeling that 1 and 6 being intermittent are something electrical.
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